New Measurements of Upsilon Spin Alignment at the Tevatron
We describe a new analysis of γ(nS) → μ+μ− decays collected in pp¯ $par p$ collisions with the CDF II detector at the Fermilab Tevatron. This analysis measures the angular distributions of the final state muons in the γ rest frame, providing new information about γ production polarization. We find...
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| Format: | Article |
| Language: | English |
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EDP Sciences
2012-06-01
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| Series: | EPJ Web of Conferences |
| Online Access: | http://dx.doi.org/10.1051/epjconf/20122804009 |
| Summary: | We describe a new analysis of γ(nS) → μ+μ− decays collected in pp¯ $par p$ collisions with the CDF II detector at the Fermilab Tevatron. This analysis measures the angular distributions of the final state muons in the γ rest frame, providing new information about γ production polarization. We find the angular distributions to be nearly isotropic up to γ pT of 40 GeV/c, consistent with previous measurements by CDF, but inconsistent with results obtained by the D0 experiment. The results are compared with recent NLO calculations based on color-singlet matrix elements and non-relativistic QCD with color-octet matrix elements. |
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| ISSN: | 2100-014X |